content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.flowable.internal.operators;
  
  import java.util.concurrent.Callable;
  
  import org.reactivestreams.Subscriber;
  
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.common.internal.functions.ObjectHelper;
  import io.reactivex.flowable.Flowable;
  import io.reactivex.flowable.internal.subscriptions.DeferredScalarSubscription;
  
  public final class FlowableFromCallable<T> extends Flowable<T> implements Callable<T> {
      final Callable<? extends T> callable;
      public FlowableFromCallable(Callable<? extends T> callable) {
          this.callable = callable;
      }
      @Override
      public void subscribeActual(Subscriber<? super T> s) {
          DeferredScalarSubscription<T> deferred = new DeferredScalarSubscription<T>(s);
          s.onSubscribe(deferred);
  
          T t;
          try {
              t = ObjectHelper.requireNonNull(callable.call(), "The callable returned a null value");
          } catch (Throwable ex) {
              Exceptions.throwIfFatal(ex);
              s.onError(ex);
              return;
          }
  
          deferred.complete(t);
      }
  
      @Override
      public T call() throws Exception {
          return ObjectHelper.requireNonNull(callable.call(), "The callable returned a null value");
      }
  }
  